The zinc-lead-silver deposit currently mined at Endeavor was discovered in 1973. Initial production commenced in 1983, and the mine operated continuously until acquired by CBH from Pasminco on September 12, 2003. The mine employs bulk mining methods and utilizes a conventional flotation mill to produce a concentrate that is sold to a third-party smelter. Mining consists of longhole stoping and ore is broken by blasting rings of holes while retreating from an open slot raise. Broken muck is picked up and loaded into underground trucks and taken to either the underground crusher or to the surface. Crushed ore is hoisted up the production shaft.
Geology and Exploration Potential
Endeavor is situated at the northern end of the Cobar Basin, a broad sedimentary basin that contains silver, lead, zinc and lesser amounts of copper mineralization contained within sulfide lenses hosted in fine-grained sedimentary rocks of the Paleozoic-aged Amphitheatre Group. The sulfide lenses that host silver and base metal mineralization at Endeavor are elliptically-shaped, steeply southwest-dipping and strike to the north-northwest. Principal ore minerals are galena, sphalerite and chalcopyrite. Silver occurs with both lead- and zinc-rich sulfide zones.
The ore reserves at Endeavor are covered by five consolidated mining leases issued by the state of New South Wales to Cobar Operations Pty. Limited ("Cobar"), a wholly-owned subsidiary of CBH Resources Ltd. ("CBH"), which in turn is a wholly owned subsidiary of Toho Zinc Co. Ltd., a company listed on the Tokyo Stock Exchange. The leases form a contiguous block of 10,121 acres in size and expire between 2019 and 2027.